Subclinical Dysfunction of Cochlea and Cochlear Efferents in Migraine: An Otoacoustic Emission Study

Beyond Vertigo: Vestibular, Aural, and Perceptual Symptoms in Vestibular Migraine

PURPOSE

To review the vestibular, aural, and perceptual symptoms of vestibular migraine (VM) that may present alongside vertigo.

RECENT FINDINGS

Increased research attention to the wide spectrum of symptoms presenting in VM patients has improved understanding of this disorder, with recent identification of five different VM phenotypes. Research into the clinical overlap between VM and other chronic vestibular syndromes such as persistent postural-perceptual dizziness and mal-de-debarquement syndrome reveals a range of vestibular symptoms and hints at pathophysiological connections between migraine and vestibular dysfunction. Studies of migraine treatment for hearing loss suggest patients presenting with aural symptoms may have an underlying diagnosis of migraine and deserve a trial of migraine preventives. Research into the neurologic basis of the perceptual disorder Alice in Wonderland syndrome has revealed brain areas that are likely involved and may help explain its prevalence in VM patients. VM is a sensory processing disorder that presents with more than just vertigo. Understanding the range of potential symptoms improves diagnosis and treatment for migraine patients whose diagnosis may be missed when only the symptoms identified in the diagnostic criteria are considered.

Migraine and Its Treatment from the Medicinal Chemistry Perspective

Migraine is a disease of neurovascular origin that affects the quality of life of more than one billion people and ranks sixth among the most common diseases in the world. Migraine is characterized by a moderate or severe recurrent and throbbing headache, accompanied by nausea, vomiting, and photo-phonophobia. It usually starts in adolescence and is twice as common in women as in men. It is classified as with or without aura and has chronic or acute treatment types according to the frequency of occurrence. In acute treatment, analgesics that relieve pain in the fastest way are preferred, while there are different options in chronic treatment. While non-specific methods were used in the treatment of migraine until the 1950s, triptans, ditans, and CGRP-receptor-dependent therapies (monoclonal antibodies and gepants) started to be used in the clinic more recently. In this Review, we focus on the synthesis, side effects, and pharmacological and pharmacokinetic properties of FDA-approved drugs used in acute and preventive-specific treatment of migraine.

A proposed association between subjective nonpulsatile tinnitus and migraine

Objective

Tinnitus is defined as the perception of sound in the absence of an external source. We propose the hypothesis that migraine can cause exacerbation of tinnitus in some patients.

Methods

English literature from PubMed has been reviewed.

Results

Studies have reported a high prevalence of cochlear symptoms in patients with migraine headaches and up to 45% of tinnitus patients have been shown to concomitantly suffer from migraine. Both conditions are thought to stem from central nervous system disturbances, involving disruption of the auditory and trigeminal nerve pathways. One proposed mechanism of this association is the modulation of sound sensitivity by trigeminal nerve activation of the auditory cortex during migraine attacks, resulting in tinnitus fluctuation in some patients. Increased brain and inner ear vascular permeability resulting from trigeminal nerve inflammation, can also cause observed headache and auditory symptoms. Tinnitus and migraine also share a number of symptom triggers including stress, sleep disturbances, and dietary factors. These shared features may help explain promising results of migraine therapies for the treatment of tinnitus.

Conclusion

Given the complex association between tinnitus and migraine, further investigation is needed to identify the underlying mechanisms and determine the optimal treatment strategies for managing migraine-related tinnitus patients.

Pathophysiology and Therapy of Associated Features of Migraine

Migraine is a complex and debilitating disorder that is broadly recognised by its characteristic headache. However, given the wide array of clinical presentations in migraineurs, the headache might not represent the main troublesome symptom and it can even go unnoticed. Understanding migraines exclusively as a pain process is simplistic and certainly hinders management. We describe the mechanisms behind some of the most disabling associated symptoms of migraine, including the relationship between the central and peripheral processes that take part in nausea, osmophobia, phonophobia, vertigo and allodynia. The rationale for the efficacy of the current therapeutic arsenal is also depicted in this article. The associated symptoms to migraine, apart from the painful component, are frequent, under-recognised and can be more deleterious than the headache itself. The clinical anamnesis of a headache patient should enquire about the associated symptoms, and treatment should be considered and individualised. Acknowledging the associated symptoms as a fundamental part of migraine has permitted a deeper and more coherent comprehension of the pathophysiology of migraine.

Risk of Vestibulocochlear Disorders in Patients with Migraine or Non-Migraine Headache

Headaches, especially migraines, have been associated with various vestibular symptoms and syndromes. Tinnitus and hearing loss have also been reported to be more prevalent among migraineurs. However, whether headaches, including migraine or non-migraine headaches (nMH), are associated with vestibular and cochlear disorders remains unclear. Thus, we sought to investigate possible associations between headache and vestibulocochlear disorders. We analyzed 10 years of data from the Smart Clinical Data Warehouse. In patients with migraines and nMH, meniere’s disease (MD), BPPV, vestibular neuronitis (VN) and cochlear disorders, such as sensorineural hearing loss (SNHL) and tinnitus, were collected and compared to clinical data from controls who had health check-ups without headache. Participants included 15,128 with migraines, 76,773 patients with nMH and controls were identified based on propensity score matching (PSM). After PSM, the odds ratios (OR) in subjects with migraine versus controls were 2.59 for MD, 2.05 for BPPV, 2.98 for VN, 1.74 for SNHL, and 1.97 for tinnitus, respectively (p < 0.001). The OR for MD (1.77), BPPV (1.73), VN (2.05), SNHL (1.40), and tinnitus (1.70) in patients with nMH was also high after matching (p < 0.001). Our findings suggest that migraines and nMH are associated with an increased risk of cochlear disorders in addition to vestibular disorders.

Distortion Product Otoacoustic Emissions and Their Suppression as Predictors of Peripheral Auditory Damage in Migraine: A Case-Control Study

Although several cochleo-vestibular symptoms are commonly associated with migraine, only a limited number of studies have been done in this regard. Some reported abnormalities in audiometry, auditory brainstem response and vestibular tests, considering these manifestations mainly related to central etiology. However, increasing evidence also suggests a peripheral involvement of the inner ear in migraine. The aim of this study was to investigate the peripheral auditory pathway in migraineurs using otoacoustic emissions (OAEs), to detect alteration of cochlear functioning and possible relationship with disease severity. Sixty-two migraineurs and sixty matched controls were enrolled in the study and underwent a routine neuro-otolaryngology examination; self-administered questionnaires were used to evaluate subjective perception of hearing disability. DPOAE and their suppression were lower in migraineurs compared to controls and significantly related to the disease duration. Altered DPOAE exposed migraineurs to the risk of affecting by migraine without aura, of presenting with ocular and/or auditory symptoms during attack and of using more painkillers. Concomitant dopaminergic symptoms and/or allodynia such as the acute non-consumption of triptans were significant determinants of decreased contralateral suppression of DPOAE among migraineurs. This potential subclinical cochlear impairment in migraine detected by OAEs may represent the earliest sign of sensorineural damage in these patients, providing a promising tool for the initial diagnosis and an opportunity to monitor disease course and treatment response over time.

Migraine and Cochlear Symptoms

Migraine is one of the most common and highest burdens of disease. As a primary cerebral dysfunction illness, migraine might exhibit other system-related symptoms, including vestibular and cochlear symptoms. With the publication of the diagnostic criteria of vestibular migraine, the link between migraine and vestibular symptoms became clear. However, the relationship between migraine and cochlear symptoms is far from straightforward. Therefore, we focus on the correlation between migraine and deafness, sudden sensorineural hearing loss, acute tinnitus, and chronic tinnitus to better understand the relationship between migraine and cochlear symptoms.

Updated review on the link between cortical spreading depression and headache disorders

INTRODUCTION

Experimental animal studies have revealed mechanisms that link cortical spreading depression (CSD) to the trigeminal activation mediating lateralized headache. However, conventional CSD as seen in lissencephalic brain is insufficient to explain some clinical features of aura and migraine headache.

AREAS COVERED

The importance of CSD in headache development including dysfunction of the thalamocortical network, neuroinflammation, calcitonin gene-related peptide, transgenic models, and the role of CSD in migraine triggers, treatment options, neuromodulation and future directions are reviewed.

EXPERT OPINION

The conventional understanding of CSD marching across the hemisphere is invalid in gyrencephalic brains. Thalamocortical dysfunction and interruption of functional cortical network systems by CSD, may provide alternative explanations for clinical manifestations of migraine phases including aura. Not all drugs showing CSD blocking properties in lissencephalic brains, have efficacy in migraine headache and monoclonal antibodies against CGRP ligand/receptors which are effective in migraine treatment, have no impact on aura in humans or CSD properties in rodents. Functional networks and molecular mechanisms mediating and amplifying the effects of limited CSD in migraine brain remain to be investigated to define new targets.

Olivocochlear efferent effects on perception and behavior

The role of the mammalian auditory olivocochlear efferent system in hearing has long been the subject of debate. Its ability to protect against damaging noise exposure is clear, but whether or not this is the primary function of a system that evolved in the absence of industrial noise remains controversial. Here we review the behavioral consequences of olivocochlear activation and diminished olivocochlear function. Attempts to demonstrate a role for hearing in noise have yielded conflicting results in both animal and human studies. A role in selective attention to sounds in the presence of distractors, or attention to visual stimuli in the presence of competing auditory stimuli, has been established in animal models, but again behavioral studies in humans remain equivocal. Auditory processing deficits occur in models of congenital olivocochlear dysfunction, but these deficits likely reflect abnormal central auditory development rather than direct effects of olivocochlear feedback. Additional proposed roles in age-related hearing loss, tinnitus, hyperacusis, and binaural or spatial hearing, are intriguing, but require additional study. These behavioral studies almost exclusively focus on medial olivocochlear effects, and many relied on lesioning techniques that can have unspecific effects. The consequences of lateral olivocochlear and of corticofugal pathway activation for perception remain unknown. As new tools for targeted manipulation of olivocochlear neurons emerge, there is potential for a transformation of our understanding of the role of the olivocochlear system in behavior across species.

Comparison of Auditory Brain Stem Responses and Otoacoustic Emission of Autism with Healthy Children

BACKGROUND

Autism is a neurodevelopment disorder, including difficulty in establishing relationships and social interaction, difficulty in communication, performing restricted, and repetitive behaviors. The impaired reception and integration of sensory information especially auditory data are one of the main characteristics of children with autism. According to various studies, the brain stem plays a key role in the reception and integration of auditory and sensory data. Hence, this study aims to comparison auditory brain stem responses (ABR) and otoacoustic emission (OAE) of autism patients with healthy children.

MATERIALS AND METHODS

This case-control study was performed on 20 autism children (4-8 years old) as case group who referred to psychiatry clinics affiliated with Tabriz University of Medical Sciences and 20 healthy age-matched as the control group. The severity of autism was evaluated by the Gilliam Autism Rating Scale (GARS). Also, ABR and OAE were recorded, and all data compared with the healthy children.

RESULTS

The latencies between the waves III-V and I-V bilaterally, and wave V bilaterally and wave I in the left ear showed a significant increase in children with autism compared to the healthy group.

CONCLUSION

This study shows that there was a reduced nerve conduction velocity in the auditory pathway of the brain stem in children with autism compared to healthy children.

The Prevalence of Different Types of Headache in Patients with Subjective Tinnitus and Its Influence on Tinnitus Parameters: A Prospective Clinical Study

Both tinnitus and headache are very prevalent conditions in the general population, with bidirectional co-occurrence of them. A number of studies revealed a high prevalence of headache in tinnitus patients; however, most of them used self-reported symptoms, questionnaires, or health databases and were retrospective. The aim of this study was to evaluate the prevalence of different types of headache in a cohort of tinnitus patients and to assess the influence of headache on tinnitus parameters, focusing on appropriate headache and tinnitus diagnosis verified by clinical examination. This prospective study involved 286 patients diagnosed with subjective non-pulsating tinnitus. Patients’ clinical information was thoroughly assessed by the multidisciplinary team, including tinnitus characteristics and severity according to the Tinnitus Handicap Inventory (THI), loudness assessed by the Visual Analogue Scale (VAS), audiometry, type of headache diagnosed according to the third edition of the International Classification of Headache Disorders, severity of headache assessed by the Numeric Rating Scale (NRS), and impact of headache using the Headache Impact Test (HIT). In total, 141 (49.3%) tinnitus patients were diagnosed with headache, most of them with tension-type headache or migraine. They were significantly younger; mostly women; had bilateral tinnitus, vertigo, and depression more frequently; and had hearing loss less frequently as compared with the non-headache group. In total, 82 (58.16%) patients had the same localization of tinnitus and headache. Younger age, female gender, higher tinnitus burden measured by THI, and coexistence of hearing loss were independent variables connected with the occurrence of headache in the tinnitus group. According to our study, headaches impact tinnitus on many different levels and may be an important co-factor for tinnitus subtyping. We recommend screening for headache coexistence in all tinnitus patients.

Menière's disease caused by CGRP - A new hypothesis explaining etiology and pathophysiology. Redirecting Menière's syndrome to Menière's disease

This paper provides a new hypothetical explanation for the etiopathology and pathophysiology of Menière's Disease (MD), which to date remain unexplained, or incompletely understood. The suggested hypothesis will explain the close connection of MD and Migraine, the coexistence of endolymphatic hydrops (ELH) and Menière attacks and the signs of inflammation detected in the inner ears of MD patients. Although as yet unproven, the explanations provided appear highly plausible and could pave the way for the generation of the first animal model of MD - an invaluable asset for developing new treatment strategies. Furthermore, if proven correct, this hypothesis could redefine and also reset the actual name of Menière's Syndrome to Menière's Disease.

Audiological Findings in Patients with Vestibular Migraine and Migraine: History of Migraine May Be a Cause of Low-Tone Sudden Sensorineural Hearing Loss

INTRODUCTION

The aim of this study was to investigate and compare the auditory findings in migraine, vestibular migraine (VM), and healthy controls.

METHODS

Twenty-eight migraine patients (56 ears), 18 VM (36 ears), and 25 healthy controls (50 ears) were included. Audiometry, speech discrimination scores, distortion product optoacoustic emission (DPOAE), and auditory brainstem response were tested.

RESULTS

The pure tone in the VM group showed higher thresholds at lower frequencies (250, 500, 1,000, 2,000 Hz) than the control group, with statistical differences observed (P250 Hz = 0.001, P500 Hz = 0.003, P1,000 Hz = 0.016, P2,000 Hz = 0.002). Compared with the healthy controls, the patients with VM had significantly lower amplitudes of DPOAE at 1 kHz (p < 0.001) and 2 kHz (p = 0.020), and the patients with migraine had lower amplitudes at 2 kHz (p = 0.042). Compared with the control group, the patients with migraine reported prolonged latency of wave V (p = 0.016) and IPL I-V (p = 0.003). The patients with VM had significant prolongation of IPL I-V (p = 0.024).

CONCLUSION

Not only the peripheral, but also the central auditory system was involved in patients with migraine and VM. In particular, lower frequencies of the auditory system were more likely to be involved in VM. The history of migraine may be a cause of low-tone sudden sensorineural hearing loss.

Auditory brainstem function in women with vestibular migraine: a controlled study

BACKGROUND

Vestibular migraine (VM) has been recognized as a diagnostic entity over the past three decades. It affects up to 1% of the general population and 7% of patients seen in dizziness clinics. It is still underdiagnosed; consequently, it is important to conduct clinical studies that address diagnostic indicators of VM. The aim of this study was to assess auditory brainstem function in women with vestibular migraine using electrophysiological testing, contralateral acoustic reflex and loudness discomfort level.

METHODS

The study group consisted of 29 women with vestibular migraine in the interictal period, and the control group comprised 25 healthy women. Auditory brainstem response, frequency following response, binaural interaction component and assessment of contralateral efferent suppression were performed. The threshold of loudness discomfort and the contralateral acoustic reflex were also investigated. The results were compared between the groups.

RESULTS

There was a statistically significant difference between the groups in the frequency following response and the loudness discomfort level.

CONCLUSIONS

The current study suggested that temporal auditory processing and loudness discomfort levels are altered in VM patients during the interictal period, indicating that these measures may be useful as diagnostic criteria.

Does Contralateral Inhibition of Transient Evoked Otoacoustic Emissions Suggest Sex or Ear Laterality Effects?

PURPOSE

The purpose of this study was to examine contralateral inhibition of transient evoked otoacoustic emissions (TEOAEs) in young adults with normal hearing as a function of ear and sex.

METHOD

Young female (n = 50) and male (n = 50) adults with normal hearing participated. TEOAEs were measured bilaterally with 80 dB peSPL nonlinear clicks and 60 dB peSPL linear clicks with and without a contralateral broadband noise elicitor at 65 dB SPL. Absolute TEOAE inhibition and normalized TEOAE inhibition (i.e., percentage of inhibition) were examined.

RESULTS

With both 80 and 60 dB peSPL evoking stimuli, there were significant main effects of ear and sex (p < .05). TEOAE levels were larger in women and in the right ear. There were no statistically significant main effects of ear and sex on absolute TEOAE inhibition (p > .05). Significant main effects of ear and sex were, however, found with normalized TEOAE inhibition (p < .05; greater in men and in the left ear). Statistically significant negative correlations and significant linear predictive relations were found between TEOAE levels and normalized TEOAE inhibitions in both ears (p < .001). There is no evidence of the same with absolute inhibition of TEOAEs (p > .05).

CONCLUSIONS

If one considers that efferent inhibition of TEOAEs is an absolute quantity, the significant effect of ear and sex on normalized inhibition and the negative association and linear predictive relationship between TEOAE level and inhibition can be viewed as spurious effects. As such, contralateral inhibition of TEOAEs does not suggest sex or ear laterality effects.

Somatosensory temporal discrimination remains intact in tension-type headache whereas it is disrupted in migraine attacks

Background and objective

Somatosensory temporal discrimination was recently reported as prolonged during migraine attacks, which is consistent with disrupted sensorial perception in migraine. However, knowledge about central sensory processing in tension-type headache is still lacking. This prospective, controlled study aimed to investigate somatosensory temporal discrimination thresholds in tension-type headache.

Methods

The study included 10 tension-type headache patients, 10 migraine patients and 10 healthy volunteers without headache. Somatosensory temporal discrimination thresholds were evaluated during the headache attacks of tension-type headache and migraine patients.

Results

Somatosensory temporal discrimination thresholds of tension-type headache patients (39.0 ± 5.5 ms for the right hand and 40.6 ± 4.6 ms for the left hand) were significantly lower than those of episodic migraine patients (137.1 ± 35.8 ms for the right hand and 118.4 ± 34.3 ms for the left hand, p < 0.0001 and p < 0.0001 respectively), and comparable to those of healthy volunteers (38.6 ± 5.3 ms for the right hand and 38.3 ± 7.2 ms for the left hand, p = 0.79 and p = 0.45 respectively).

Conclusion

Central sensory processing, as tested by somatosensory temporal discrimination, was remarkably disrupted during the headache attacks in migraineurs, whereas it remained intact in the tension-type headache patients.

Effects of gestational and lactational exposure to low dose mercury chloride (HgCl2) on behaviour, learning and hearing thresholds in WAG/Rij rats

We investigated the effects of inorganic mercury exposure during gestational/lactational periods on the behaviour, learning and hearing functions in a total of 32, 5-week-old and 5-month-old WAG/Rij rats (equally divided into 4 groups as 5-week and 5-month control mercury exposure groups). We evaluated the rats in terms of locomotor activity (LA), the Morris-water-maze (MWM) test and the passive avoidance (PA) test to quantify learning and memory performance; we used distortion product otoacoustic emission (DPOAE) tests to evaluate hearing ability. There were no significant differences between the 5-week-old rat groups in LA, and we detected a significant difference (p < 0.05) in the HgCl₂-treated group in PA, MWM and DPOAE tests compared with the control group. The HgCl₂-treated 5-week-old group exhibited worse emotional memory performance in PA, worse spatial learning and memory performances in MWM. There were no significant differences between the groups of 5-month-old rats in LA, MWM or PA. However, the DPOAE tests worsened in the mid- and high-frequency hearing thresholds. The HgCl₂-treated 5-month-old group exhibited the most hearing loss of all groups. Our results convey that mercury exposure in young rats may worsen learning and memory performances as well as hearing at high-frequency levels. While there was no statistically significant difference in the behavior and learning tests in adult rats, the DPOAE test produced poorer results. Early detection of effects of mercury exposure provides medicals team with an opportunity to determinate treatment regimens and mitigate ototoxicity. DPOAE test can be used in clinical and experimental research investigating heavy metal ototoxicity.

Prophylactic treatment of vestibular migraine

Introduction

Vestibular migraine (VM) is now accepted as a common cause of episodic vertigo. Treatment of VM involves two situations: the vestibular symptom attacks and the period between attacks. For the latter, some prophylaxis methods can be used. The current recommendation is to use the same prophylactic drugs used for migraines, including β-blockers, antidepressants and anticonvulsants. The recent diagnostic definition of vestibular migraine makes the number of studies on its treatment scarce.

Objective

To evaluate the efficacy of prophylactic treatment used in patients from a VM outpatient clinic.

Methods

Review of medical records from patients with VM according to the criteria of the Bárány Society/International Headache Society of 2012 criteria. The drugs used in the treatment and treatment response obtained through the visual analog scale (VAS) for dizziness and headache were assessed. The pre and post-treatment VAS scores were compared (the improvement was evaluated together and individually, per drug used). Associations with clinical subgroups of patients were also assessed.

Results

Of the 88 assessed records, 47 were eligible. We included patients that met the diagnostic criteria for VM and excluded those whose medical records were illegible and those of patients with other disorders causing dizziness and/or headache that did not meet the 2012 criteria for VM. 80.9% of the patients showed improvement with prophylaxis (p < 0.001). Amitriptyline, Flunarizine, Propranolol and Topiramate improved vestibular symptoms (p < 0.001) and headache (p < 0.015). The four drugs were effective in a statistically significant manner. There was a positive statistical association between the time of vestibular symptoms and clinical improvement. There was no additional benefit in hypertensive patients who used antihypertensive drugs as prophylaxis or depressed patients who used antidepressants in relation to other prophylactic drugs. Drug association did not show statistically significant results in relation to the use of a single drug.

Conclusions

Prophylactic medications used to treat VM improve the symptoms of this disease, but there is no statistically significant difference between the responses of prophylactic drugs. The time of vestibular symptom seems to increase the benefit with prophylactic treatment.

Migraine patients consistently show abnormal vestibular bedside tests

Migraine and vertigo are common disorders, with lifetime prevalences of 16% and 7% respectively, and co-morbidity around 3.2%. Vestibular syndromes and dizziness occur more frequently in migraine patients. We investigated bedside clinical signs indicative of vestibular dysfunction in migraineurs. Objective To test the hypothesis that vestibulo-ocular reflex, vestibulo-spinal reflex and fall risk (FR) responses as measured by 14 bedside tests are abnormal in migraineurs without vertigo, as compared with controls. Method Cross-sectional study including sixty individuals – thirty migraineurs, 25 women, 19-60 y-o; and 30 gender/age healthy paired controls. Results Migraineurs showed a tendency to perform worse in almost all tests, albeit only the Romberg tandem test was statistically different from controls. A combination of four abnormal tests better discriminated the two groups (93.3% specificity). Conclusion Migraine patients consistently showed abnormal vestibular bedside tests when compared with controls.

Vestibular migraine: comparative analysis between diagnostic criteria

INTRODUCTION

There is a strong association between vertigo and migraine. Vestibular migraine (VM) was described in 1999, and diagnostic criteria were proposed in 2001 and revised in 2012.

OBJECTIVE

To compare the diagnostic criteria for VM proposed in 2001 with 2012 criteria with respect to their diagnostic power and therapeutic effect of VM prophylaxis.

METHODS

Clinical chart review of patients attended to in a VM clinic.

RESULTS

The 2012 criteria made the diagnosis more specific, restricting the diagnosis of VM to a smaller number of patients, such that 87.7% of patients met 2001 criteria and 77.8% met 2012 criteria. Prophylaxis for VM was effective both for patients diagnosed by either set of criteria and for those who did not meet any of the criteria.

CONCLUSIONS

The 2012 diagnostic criteria for VM limited the diagnosis of the disease to a smaller number of patients, mainly because of the type, intensity, and duration of dizziness. Patients diagnosed with migraine and associated dizziness demonstrated improvement after prophylactic treatment of VM, even when they did not meet diagnostic criteria.

A study of cochlear and auditory pathways in patients with tension-type headache

Background

The purpose of this study was to systematically evaluate the function of cochlear and auditory pathways in patients suffering from tension-type headache (TTH) using various audiological methods.

Methods

Twenty-three TTH patients (46 ears) and 26 healthy controls (52 ears) were included, and routine diagnostic audiometry, extended high-frequency audiometry, acoustic reflex (ASR), transient evoked otoacoustic emissions (TEOAEs), distortion product otoacoustic emissions (DPOAEs) and suppression TEOAEs were tested.

Results

The TTH group showed higher thresholds (P < 0.05) for both pure tone and extended high-frequency audiometry at all frequencies except for 9, 14 and 16 kHz. All ASR thresholds were significantly higher (P < 0.05) in the TTH group compared with the controls, except for the ipsilateral reflex at 1 kHz, but the threshold differences between the ASR and the corresponding pure tone audiometry did not differ (P > 0.05). For the DPOAEs, the detected rates were lower (P < 0.05) in the TTH group compared with the controls at 4 and 6 kHz, and the amplitudes and signal to noise ratio (S/N) were not significantly different between groups. No differences in the TEOAEs (P > 0.05) were observed for the detected rates, amplitudes, S/Ns or contralateral suppression, except for the S/Ns of the 0.5-1 kHz TEOAE responses, which were significantly higher (P < 0.05) in the TTH group.

Conclusions

The results of our study indicate that subclinical changes in cochlear function are associated with TTH.

Migraine is associated with altered processing of sensory stimuli

Migraine is associated with derangements in perception of multiple sensory modalities including vision, hearing, smell, and somatosensation. Compared to people without migraine, migraineurs have lower discomfort thresholds in response to special sensory stimuli as well as to mechanical and thermal noxious stimuli. Likewise, the environmental triggers of migraine attacks, such as odors and flashing lights, highlight basal abnormalities in sensory processing and integration. These alterations in sensory processing and perception in migraineurs have been investigated via physiological studies and functional brain imaging studies. Investigations have demonstrated that migraineurs during and between migraine attacks have atypical stimulus-induced activations of brainstem, subcortical, and cortical regions that participate in sensory processing. A lack of normal habituation to repetitive stimuli during the interictal state and a tendency towards development of sensitization likely contribute to migraine-related alterations in sensory processing.

Migraine with aura is associated with impaired colour vision: Results from the cross-sectional German DMKG headache study

BACKGROUND

Hypersensitivity to light, noise and odour are pivotal clinical characteristics of migraine associated with enhanced cortical excitability and dysfunctional habituation. However, little is known about the integrity of basic sensory functioning in migraine on a population-based level.

METHODS

A total of 129 participants with migraine (105 without aura, MwoA, 24 with aura, MA) and 522 healthy controls without headache 12 months prior to baseline were included from a sample of the DMKG study and underwent standardised clinical sensory testing of smell, taste, hearing and vision.

RESULTS

After adjustment for age, sex, smoking status and history of head injuries, the chance of impaired colour perception was significantly higher in MA compared to controls (odds ratio, OR=3.20; 95% CI=1.20-8.53) and MwoA (OR=3.62; 95% CI=1.31-9.97). Compared to MwoA, MA also had an increased chance of smell (OR=3.20; 95% CI=0.98-10.42) and taste (OR=2.58; 95% CI=0.90-7.40) impairment.

CONCLUSIONS

In this cross-sectional, population-based study on sensory functioning in migraine participants, colour vision was impaired interictally in MA compared to MwoA and controls.

Assessment of cochlear and auditory pathways in patients with migraine

PURPOSE

In this study, we aimed to determine the function of the cochlea and peripheral and central auditory pathways with migraine.

MATERIALS AND METHODS

Fifty-eight patients with migraine and 40 healthy subjects were assessed using routine diagnostic audiometry along with transient evoked otoacoustic emissions (TOAEs), distortion product otoacoustic emissions (DPOAEs), and auditory brainstem response (ABR) at high and low repetition rate frequencies.

RESULTS

Nearly two thirds of patients with migraine had one or more abnormalities in electrophysiological testing. Compared with control subjects, patients reported significant lowering of TOAEs amplitude at frequencies of 1 kHz (right: P = .0003; left: P = .002), 3 kHz (right: P = .025), and 4 kHz (right: P = .019); prolonged wave III latency (right: P = .009); and I-V interpeak latency (IPL) (left: P = .024) at high repetition rate frequencies. Significant correlations were identified between age, duration of illness and frequency of migraine and TOAEs total response and at amplitude of 4 kHz, amplitudes of DPOAEs at 1, 1.5, 2, 3, and 5 kHz and I, III and wave latencies and I-V IPL of ABR at high rate frequencies.

CONCLUSIONS

These data suggest that subclinical changes in cochlear function and auditory pathways are associated with chronic migraine. It is possible that migraine could be accompanied by compromise of blood supply of auditory system.

Vestibular evoked myogenic potentials to sound and vibration: characteristics in vestibular migraine that enable separation from Meniere's disease

OBJECTIVES

It can be difficult to distinguish vestibular migraine (VM) from Menière's disease (MD) in its early stages. Using vestibular-evoked myogenic potentials (VEMPs), we sought to identify test parameters that would help discriminate between these two vestibular disorders.

METHODS

We first recorded ocular and cervical VEMPs (oVEMP/cVEMP) to air-conducted clicks and bone-conducted vibration in 30 control participants, 30 participants with clinically definite VM and 30 participants with clinically probable VM. Results were compared with a group of 60 MD patients from a previous study. oVEMPs and cVEMPs were then recorded at octave frequencies of 250 Hz to 2000 Hz in 20 controls and 20 participants each with clinically definite VM and MD. Inter-aural amplitude asymmetry ratios and amplitude frequency ratios were compared between groups.

RESULTS

For click, tendon-hammer-tap and minishaker-tap VEMPs, there were no significant differences in reflex amplitudes or symmetry between controls, definite VM and probable VM. Compared with MD patients, participants with VM had significantly fewer reflex abnormalities for click-cVEMP, click-oVEMPs and minitap-cVEMPs. The ratio of cVEMP amplitude generated by tone bursts at a frequency of 0.5 kHz to that generated by 1 kHz was significantly lower for MD affected ears than for VM or controls ears. cVEMP asymmetry ratios for 0.5 kHz tone bursts were significantly higher for MD than VM.

CONCLUSIONS

The 0.5/1 kHz frequency ratio, 0.5 kHz asymmetry ratio and caloric test combined, separated MD from VM with a sensitivity of 90.0% and specificity of 70.0%.

Cortical inhibition and habituation to evoked potentials: relevance for pathophysiology of migraine

Dysfunction of neuronal cortical excitability has been supposed to play an important role in etiopathogenesis of migraine. Neurophysiological techniques like evoked potentials (EP) and in the last years non-invasive brain stimulation techniques like transcranial magnetic stimulation (TMS) and transcranial direct current stimulation gave important contribution to understanding of such issue highlighting possible mechanisms of cortical dysfunctions in migraine. EP studies showed impaired habituation to repeated sensorial stimulation and this abnormality was confirmed across all sensorial modalities, making defective habituation a neurophysiological hallmark of the disease. TMS was employed to test more directly cortical excitability in visual cortex and then also in motor cortex. Contradictory results have been reported pointing towards hyperexcitability or on the contrary to reduced preactivation of sensory cortex in migraine. Other experimental evidence speaks in favour of impairment of inhibitory circuits and analogies have been proposed between migraine and conditions of sensory deafferentation in which down-regulation of GABA circuits is considered the more relevant pathophysiological mechanism. Whatever the mechanism involved, it has been found that repeated sessions of high-frequency rTMS trains that have been shown to up-regulate inhibitory circuits could persistently normalize habituation in migraine. This could give interesting insight into pathophysiology establishing a link between cortical inhibition and habituation and opening also new treatment strategies in migraine.